1. Field of the Invention
The present invention relates to a method for optimizing the working conditions of a cutting tool in the shaping of parts by the removal of chips, primarily turning, milling and drilling.
2. Brief Discussion of the Related Art
The aim of the French standard NF E66-520 is to define a method called Tool/Workpiece Combination (COM) intended to determine the working conditions of a cutting tool so as to deduce therefrom an optimum range of use in production. In practice, as recalled in the introduction to that standard: “These days, it is essential to get it right straight away while improving and predimensioning the production system.”
Following the method recommended by this standard is a practice that has become fairly widespread these days. Very schematically, it will be recalled that the standard stipulates carrying out tests, after having defined a stable operating point for the tool and for the machine (qualification point), by varying, independently of one another, about this operating point, at least two parameters which will be, for example, the cutting speed Vc and the advance f of the tool. The recordings made during these tests make it possible to determine the variation of the energy consumed by the machining operation as a function of the variable Vc and f, which energy is called specific cutting energy or effort Kc (for the case of turning). The minimum values of this energy make it possible to determine a range between maximum and minimum values of the parameters Vc and f, within which ranges the machining operation is optimized. It is possible to refine these operations according to the standard by applying various correlations of the optimum data with other criteria such as monitoring the chips produced and the surface condition obtained.
The normative methodology requires a number of tests to be carried out for the results to have a statistical value in producing the curves (or databases) which will be used in choosing the optimum operating conditions of the tool. Implementing these tests presents two drawbacks: the requirement to instrument the machine and the tool that is to be “predimensioned” for series production and the expenditure of time needed to carry out the tests for determining optimal operation.
There is therefore a need to simplify the COM methodology by eliminating the instrumentation of a machine and by saving time in the recording of the parameters that are used for this methodology.